Electrical and/or electronic components and systems are often mounted in cabinets which may be referred to as switchgear cabinets. Simply because such components are electrical in nature, they evidence energy losses manifested as heat. And heat causes the temperature of such components and systems to rise, sometimes to an undesirable or intolerable level.
While most electrical and electronic components and systems are designed to operate at a temperature above room ambient, there is also an upper limit to such temperature. And depending upon the size and number of components and systems in a particular switchgear cabinet and the "duty cycle" at which such components and systems are operated at or near their rated outputs, additional cooling may be required.
An air conditioning arrangement for a switchgear cabinet having a cooling apparatus, a control arrangement and sensors, is described in DE 38 11 189 C2. In this known switchgear cabinet air conditioning arrangement, the cooling apparatus is switched-on and switched-off both on the basis of the signals from temperature sensors and on the basis of the signal from a moisture/humidity sensor.
In an air conditioning arrangement disclosed in EP 0 381 592 A2, a plurality of heat exchanger devices are provided, which are supplied from a common coolant tank. The coolant can be conducted to a plurality of heat generators by means of a control arrangement.
An alternative air conditioning arrangement is described in DE 43 37 692 A1, wherein a cooling effect, corresponding to the quantity of heat generated by an electronic apparatus, can be produced both from n cooling units and from n+1 cooling units so that, with n+1 cooling units, each cooling unit has an adequate reserve. In known switchgear cabinet air conditioning arrangements, those air conditioning components which control cabinet interior temperature are often mounted inside the switchgear cabinet.
While the earlier arrangements have been generally satisfactory for the intended purpose, they lack the capability to implement any one or more of several control "strategies" for cabinet temperature regulation. That is, such earlier arrangements are understood to be incapable of controlling temperature on the basis of, e.g., time, loading of the electrical components/systems in the cabinet (as evidenced by the current drawn thereby), humidity, normal and emergency operating circumstances, efficiency (energy conservation), noise level and other parameters.